Tenofovir how to protect pregnancy?
(1) on the fetus and infant: tenofovir safety of pregnancy is Class B. Placental permeability of 95-99%, 19 times the dose of no fetal toxicity or reproductive injury in rats or rabbits. So far abroad tenofovir or lamivudine have a lot of clinical experience in pregnancy, there is no evidence of teratogenicity or adverse reactions to pregnancy. Embryos are non-toxic and do not cause deformities on the fetus. Tenofovir or lamivudine can be secreted in milk but is not harmful to newborns.
(2) the mother of hepatitis: tenofovir has a protective effect on the whole process of pregnancy, 3,4 months after taking aminotransferase reduced to normal, you can start pregnancy. By the end of pregnancy, most people have a negative serum virus, which can block intrauterine and childbirth transmission. The efficacy of tenofovir is stronger than lamivudine, almost no resistance; lamivudine resistance rate of 20% within 1 year, taking full risk of drug resistance during pregnancy.
(3) For mothers with chronic sex: serum virus levels exceeding 6 copies / ml may be transmitted intrauterine or childbirth, postnatal hepatitis B vaccine and hepatitis B immunoglobulin can not be prevented. Should start from the 28th week of pregnancy service lamivudine to stop delivery, more than 10 years have been implemented at home and abroad, safe and reliable.
Tenofovir more powerful, but not as good as using lamivudine, the reasons need to start from scratch:
1. Half of the fetus genes from the father, this half is like pregnant women are allografts, in order to avoid the mother's immune system on the rejection of the fetus, pregnant women must reduce the immune rejection (clearance) response. After delivery is equal to the graft is gone, the immune clearance response increased, 40% of mother-to-carrier will occur after delivery of hepatitis.
2. Lamivudine efficacy is weak, only medication for 3 months, little rebound after stopping; tenofovir powerful, rebound after stopping may also be strong.